Urology: uric acid calculi: practice question

A General Surgery question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Surgery · Urology: uric acid calculi

Sample item

A 55-year-old man with gout has a stone that is not seen on plain radiography but is visible on CT. His urine pH is 5.0. Which measure helps dissolve it?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Oral potassium citrate to raise urinary pH to about 6.5

Uric acid stones are radiolucent and form in persistently acidic urine, being soluble at a pH above about 6.5. Oral alkalinisation with potassium citrate, with high fluid intake, can dissolve them, and allopurinol can lower urate production. Acidifying the urine worsens crystallisation.

Option by option

  • A. Thiazide diuretic

    Thiazides reduce urinary calcium but raise serum urate, and are used in calcium stones.

  • B. Ammonium chloride to acidify the urine

    Acidification lowers pH and promotes more uric acid precipitation.

  • C. Oral potassium citrate to raise urinary pH to about 6.5 (correct)

    Raising urinary pH increases uric acid solubility and dissolves the stone.

  • D. Dietary calcium restriction

    Calcium restriction raises oxalate absorption and is not useful for uric acid stones.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is C, Oral potassium citrate to raise urinary pH to about 6.5. Uric acid stones are radiolucent and form in persistently acidic urine, being soluble at a pH above about 6.

Why is "Thiazide diuretic" not the answer?

Thiazides reduce urinary calcium but raise serum urate, and are used in calcium stones.

Why is "Ammonium chloride to acidify the urine" not the answer?

Acidification lowers pH and promotes more uric acid precipitation.

Why is "Dietary calcium restriction" not the answer?

Calcium restriction raises oxalate absorption and is not useful for uric acid stones.

What concept does this question test?

It tests Urology: uric acid calculi in General Surgery. 5. Oral alkalinisation with potassium citrate, with high fluid intake, can dissolve them, and allopurinol can lower urate production. Acidifying the urine worsens crystallisation.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Urology: uric acid calculi?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.